For the duration of the spell, the area of effect was protected against silence spells. The area of effect was a sphere whose radius was 10 ft (3 m) per level of the caster, and was immobile. Any silence effects inside or overlapped by this volume did not operate, allowing speaking, spell-casting, etc.
No verbal component was required, allowing this spell to be cast even in a silenced area. The material component was a pinch of diamond powder worth at least 50 gp that was tossed into the air as the spell was cast.